In general, a radiator cools the coolant that cools the engine of a vehicle, and a condenser cools the refrigerant used by an air conditioner of the vehicle. The radiator and the condenser are usually laid out so that they may be cooled by the flow of air drawn into the vehicle from the front when the vehicle is traveling.
However, the flow of air generated when the vehicle travels may become insufficient during traffic congestion. Thus, for example, a cooling fan is typically provided behind a radiator and a condenser. The cooling fan is able to generate a flow of air in the same direction as the flow of air generated when the vehicle travels. The radiator, the condenser, the cooling fan, and other components are accommodated in a box-shaped fan shroud to effectively use the flow of air of the cooling fan.
In recent years, various vehicle cooling fan devices have been proposed that include a fan shroud and a cooling fan.
For example, patent document 1 proposes a vehicle heat exchanger that includes two cooling fans and one fan controller. The fan controller generates a relatively large amount of heat and thus needs to be cooled properly. In patent document 1, the fan controller is placed on a fan shroud at a position separated from the central portion of the fan shroud to allow the fan controller to be cooled by some of the air flowing from one of the cooling fans. Further, in patent document 1, a duct extends from the fan controller toward the other cooling fan so that some of the air flowing from the other cooling fan is drawn to the fan controller. Thus, the fan controller is properly cooled even when one of the cooling fans stops. A partition wall, which partitions operation areas of the cooling fans, extends between the adjacent cooling fans toward the radiator. As described in patent document 1, a communication section may be provided in the upper portion of the partition wall, which is near the fan controller, to increase the air flowing to the fan controller.
Patent document 2 describes two cooling fans that have a larger diameter to increase the amount of the flowing air. The two cooling fans partially overlap each other in a fan shroud. The high velocity of the flowing air where the cooling fans overlap each other may produce annoying noise when the cooling fans are driven. Thus, the fan blades have a special shape to reduce noise. In patent document 2, since the cooling fans overlap each other, a partition wall is not provided to partition the operation areas of the cooling fans.